UPSC Prelims 2021 Q58: Geography – Atmosphere & Climatology
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer: (c) Both 1 and 2
Explanation
Ocean Warm Currents: Tropical vs Temperate Zones
| Statement | Claim | Verdict | Detail |
|---|---|---|---|
| 1 | Tropical zone: western sections of oceans warmer than eastern (due to trade winds) | TRUE | Trade winds blow east-to-west in tropics, pushing warm water westward - creating warm western boundary currents (Gulf Stream, Kuroshio, Brazil Current, East Australian Current). Eastern sides get cold upwelling (California Current, Peru/Humboldt Current, Benguela Current). |
| 2 | Temperate zone: westerlies make eastern sections warmer than western | TRUE | Westerlies blow west-to-east in temperate zones, pushing warm water eastward. In North Atlantic, the Gulf Stream extension (North Atlantic Drift) carries warmth to Europe. Combined with Coriolis force, this makes eastern sides of oceans in temperate zone warmer than western sides. |
Both statements are correct. Answer: (c).
Answer: (c) Both 1 and 2.
Why each option is right or wrong
- (a) Incorrect. Statement 2 is also correct - westerlies do carry warm water eastward in temperate zones.
- (b) Incorrect. Statement 1 is also correct - trade winds warm the western tropical oceans.
- (c) CORRECT. Both statements are true. Tropical trade winds push warm water westward (Gulf Stream, Kuroshio); Temperate westerlies push warm water eastward (warming Europe via North Atlantic Drift).
- (d) Incorrect. Both statements are correct explanations of ocean current geography.
Key point
Tropical trade winds = warm water westward (Gulf Stream, Kuroshio); cold upwelling on eastern sides (California, Peru). Temperate westerlies = warm water eastward (North Atlantic Drift warms Europe). Both statements correct.
Remember
Both statements are correct: (1) In the tropical zone, trade winds (east-to-west) make the WESTERN sections of oceans warmer than eastern; (2) In the temperate zone, westerlies (west-to-east) make the EASTERN sections warmer than western. Answer: (c) Both 1 and 2.
Common mistakes
- Confusing trade wind direction (east-to-west in tropics) with westerly direction (west-to-east in temperates).
- Not knowing why Europe (temperate) is warmer than Canada at same latitude: North Atlantic Drift (Gulf Stream extension).
- Missing that western coasts of tropical continents (Peru, California, Namibia) have cold currents and deserts due to upwelling.
Exam tip
Wind-current pattern: Tropics = trade winds (E to W) - warm western oceans. Temperate = westerlies (W to E) - warm eastern oceans. Cold upwelling = eastern tropical coasts (Peru, California, Benguela). Warm western tropical coasts (Gulf of Mexico, Kuroshio).
Sources
- NCERT Class XI Fundamentals of Physical Geography - Chapter on Ocean Currents
- NOAA - Global Ocean Circulation Documentation